A case of COVID-19 reinfection in the UK.

Protective immunity following COVID-19 infection is not yet fully understood. An understanding of COVID-19 reinfection will be key in guiding government and public health policy decisions in the coming months. This report describes two distinct infective episodes of COVID-19 occurring in the same individual, at the time of writing the first published case in the UK. In April 2020 a 25-year-old UK doctor exhibited classical COVID-19 symptoms, including fevers, headaches, and fatigue. A COVID-19 nucleic acid amplification test (NAAT) at the time returned negative. However, a follow-up antibody test in May 2020 returned positive. In October 2020 the same individual exhibited coryzal symptoms and headaches. He was COVID-19 NAAT tested and found to be positive. There was exposure to high viral load prior to reinfection. Overall the second infection was symptomatically milder, with a faster recovery. This evidence for reinfection poses challenges for public health and vaccination efforts to protect against the COVID-19 pandemic. © Royal College of Physicians 2021. All rights reserved.